feat: LuaJIT Animations (#1001)

## What are the changes about?
TL;DR:
![ly_meme](/attachments/f4c3a93b-6ede-42ab-a351-292e2105d4e2)

Slaps the entire LuaJIT runtime onto Ly, allowing for the creation of custom dynamic animations like GameOfLife, ColorWave, Doom, etc.
This PR adds the [ziglua](https://github.com/natecraddock/ziglua?ref=zig-0.16) dependency for its zig bindings and considerable buildtime config (mainly lua version selection).

### Example
 <video src="/attachments/3f91cf72-ae24-459c-8ef6-099f71e866fd" title="Screencast_20260519_172320" controls></video>
```lua
ly.frame_delay = 5
local timer = 0
local clock = os.clock()
local clock_diff = 0
function draw()
	timer = timer + 1
	byte = string.byte(' ')
	clock_diff = os.clock() - clock
	clock = os.clock()
	timer = timer + clock_diff
	for x = 0, ly.width-1 do
		for y = 0, ly.height-1 do
			local xc = 0xFF
			if x < 255 then xc = ((x + math.floor(timer / 2)) * 3) % 255 else xc = 0 end
			local yc = 0xFF
			if y < 255 then yc = ((y) * 3) % 255 else yc = 0 end
			ly.putCell(byte, xc, bit.bor(xc, yc), x, y)
		end
	end
end
```

### The API

The API that Ly gives to the user is minimal. A table is globally available, named `ly`, which provides the following:

| Member  | Purpose  |
|---------|---------|
| `ly.width` & `ly.height` | Respective Width/Height from the `TerminalBuffer` |
| `ly.putCell(byte, fg, bg, x, y)` | Literally `Cell.init(byte, fg, bg).put(x, y)`.|
| `ly.clock()` | The current real-time, in microseconds. |

### Error Handling

On a Lua Error, Ly won't quit but will instead paint the entire background red. The lua error in question can be found in the Ly log file and on-screen.
```log
2026-05-19 16:13:40 [err/Lua] Error (Cannot call draw()): attempt to call a nil value
2026-05-19 11:05:51 [err/Lua] Lua Error: ...dsammyt/programming/probe/ly/scratch/testConfig/test.lua:30: bad argument #1 to 'ipairs' (table expected, got number)
```

## Pre-requisites

- [X] I have tested & confirmed the changes work locally
- [X] I have run `zig fmt` throughout my changes

Reviewed-on: https://codeberg.org/fairyglade/ly/pulls/1001
Reviewed-by: AnErrupTion <anerruption+codeberg@disroot.org>

res/config.ini

@@ -25,6 +25,7 @@ allow_empty_password = true
 # colormix -> Color mixing shader
 # gameoflife -> John Conway's Game of Life
 # dur_file -> .dur file format (https://github.com/cmang/durdraw/tree/master)
+# lua -> user-made animation written in LuaJIT
 animation = none
 
 # Delay between each animation frame in milliseconds
@@ -298,6 +299,9 @@ login_defs_path = /etc/login.defs
 # no need to add `exec "$@"` at the end
 logout_cmd = null
 
+# The file pointing to the Lua file to be used when using the Lua animation option
+lua_animation_file = $CONFIG_DIRECTORY/ly/example.lua
+
 # General log file path
 # If null, syslog will be used instead
 ly_log = /var/log/ly.log